Portable power driven percussive tool



May 3Q, 1933. DECKER 1,911,814

PORTABLE POWER DRIVEN PERCUSSIVE TOOL Filed April 29 1931 3 Sheets-Sheet l A. G. DECKER -May 30,-"1933.

PORTABLE POWER DRIVEN PERCUSSIVE TOOL Filed April 29 1951 3 Sheets-Sheet 2 r w w A. G. DECKER May 30, 1933.

PORTABLE POWER DRIVEN PERCUSSIVE TOOL Filed April 29 1951 3 Sheets-Sheet 5 Patented May 30, 1933 ALoivzo, G.- DECKER, or BALTIMORE 011mm MARYLAND,ASSIGNOR TO THE BLACK &

H .hp' 1iati6n h1i1fa ri1 2s, The invention relates to 'a" portable] power driven percussive tool for hammer of the reciprobating' rain type! In the form in which thismachiiiehas'been' developed and reduced to practice it consists o'iia sourceofrotary motion 'eleetric "motor: f 013'; a flexible shaft, or this "motion: befoibtained from an her. n n t;" i Th ry mot' ioii' is" in turn conv r e 'by' niean s of a crankor e'c'tientric fa cohnecting into 'a reciprecating motionof a'pluiiger o rjcros's head. By the conversion of rota ry' mot'ion to reciprocating movementflin: this ','way a harmonic ,motion of the plungeror cross headresults, 5 It is, I h0we'ver',;jnot essential that the reeipr'ocatingmotion of the piston or 'plu nger be harni'oniq as the cross-head may""withir i i the" sc pe, of the invention be reeiprocated in "suitable and convenient manner? '3 E j I ,1

The cross head is 'in turn mounted on and connected to 1 the 'ra'm which it actuates and re1atively*"towhich the ram is adapted to have aflrecip'rociitingmotion ,the motion of the piston "or plunger communicated to the" ram"by"and throughic ertain resilient means, preferablyinthe form or one or'more pneumatic members, which provide for a vibratorymotion of the .ram relatively to the pl-unge'rfthe periodicy of which .vibratory motion is determined by and is preferabl'y'aTunction ofthe rotative speed, the radius of'the crank, the relative tension of the resilient'iiienibers and the mass of the rain, it beiiig understood that the unit com prising the ram andresilient members has a natural period of vibration or oscillation. In the present instance this natural period of vibration is in the preferred form of the hammer an integral factor of the speed of rotation of'the crank sothat there are one or two or more complete revolutions of the crank or other actuating member for each blow or stroke of the'ram, whereby a speed of the ram may be obtained which is far in excess of that obtained from the crank alone. In the operationof the tool embodying the invention I in the preferred form the crank or any corresponding-shaft from which the motion of the machine is obtained may have 11%) v 'j a r PORTABLE-,PQWER DRIV]3H T PERCUSSIVE TOOL 1931f Serial no; saaeia'.

revolutions of the crahk to'ea'ch a no 'rmal speed er from 180O to 2,000 revolu- By thus designingand'fproportioningthe apparatus the speed (bi-"the ram being a function of the tension and relativestrength of the resilient 'members," the mass of the ram and the length of the stroke, the resilient members become a ing means whereby the motion ot'the crank, the momentum of the ram and the resilient thrust are combined to produce the vibration or stroke of the ram.

part of the actuat 1 In the preferred form of hammer disclosed, the resilient members are eacliin the form of a pneumatic pad 'or flexible container filled with air or any other convenient gas and under pressure with suitable Valve means whereby they may be further inflated to the desired pressure when and if at any time they become slightly deflated or the valve may be omitted and the pneumatic pads may be in the form of closed inflated containers on the order of a tennis ball which, after wearing out or becoming deflated, can be thrown away and replaced at a nominal cost.

- In the accompanying drawings I have illustrated a reciprocating tool embodying the features of the invention in the preferred form.

In the drawings:

Figure 1 is an elevation of the tool, portions being broken away and shown in section.

- Figure 2 is a fragmentary section at right angles to thepla-ne of Figure 1 and on the line 2, 2.

Figure 3 is a section on the line 3, 3 transverse to the axis.

29 echi uu irae '".in' ai u e QmP Ti l I w I I j .i'lh a t9 (if h m n l ierri pi Figure 4 is a section on the line 4, 4 in Figure 2, representing a plane of the axis at right angles to the plane of Figure 2.

Figure 5 is a section on the line 5, 5 in Figure 4.

erefi is. ma e e with n Pit P eefioera fs Q PQ -I i Figure the form of a ball.

1?; Figure 8 is.awieweorrespon'din to Fig- 4f |1,;,\ V secured to thegea cas ngegbelow-the motor a t a sen -W eee e fw e sprea sui abl g i 'ea lmelf", Q If fra guide I, which I in the. preferred foijrfiii's eedjnw ruiyj irtm the barrel 5 to; reduce transmission of heat to the b 1 "the y -1 1P? 9t??? the: 1

i9 9: W is -m hes wi h 'aite'e h s t 1 on the idler shaft 12,wh ich carries a similar toothed gear, 14 meshing; in operation with LThe 'shafts l2la'n di 1615311 9 ,mounted repectively n suitableb'earings 17v and 18, upp eei t ge as g 'rh eran shaft' lfi, in turn, carries a crank disk 19 in which thecrank pin 20 is eccentrieallyinountedflThe crank pin is in turnfen'gaged'by a connecting rod 21 proy iiledjwith 'a bearing 22 surrounding the crank pin. This connecting rod is in turn :securedlat'itslower end to the center of, the

' crossbar of a yoke 25, the connection being preferably of a conveniently disengageable type.v In the form shown the transverse 'pin, 26 isl passed through a socket-'27 on the yo ke' -and through the end 1 of the connecting roda't 28 wliich is seated in the socket. I This connection may, however,,be made in any suitable ma nner. I v

the/form of hammer-shown, in Figures 1 to 4, the side bars 30, 31 of the yoke are in-. the;f orm of round rods 01' bolts threaded atone. endinto the cross bar 24 and reduced at their lower ends at 32, the reducedportions providing shoulders or abutments- 33, beingpassed through a crosshead or plung- 1s a View showlng the in er member 34 shown in the form of a transverse plate. The side bars 30, 31 of the yoke are secured below the plate by means of nuts 35 or in any suitable manner.

This cross head, plunger or piston 34, is located within, a, suitable, cavity ,36 the rainf ffi, ivhieh is elbsedfittheitop may suitable manner as by means of a removable 'pnteev held by screws 38. Cross head 34 is supported within the rant-6 between" pneumatic pads-ea temwand "4O -above feach of which pads bears on One sid agaiins't the *crosshead"or' piston 34 which as best illustrated in Figure 2, is preferably shaped to 'conform to the pads.

The lower pad 39 bears on ;its oppositeside against the bottom of the,:riam 6 which is also .shaped;.to :.t i e h d 'th pp' n we m me its 1 p e sideagainst the cover or top ,plate 37 .whic'hisilike wise shaped to fit .-the,,top cit-his pad 40. Thecross head, as shown, a ars 1 41 less. 3Pr0'1' ti11r; nt sl ts in the sides of the cavity 36 The, r ars, l g e e eeg d b t S d 11m 39 ldifi .QSQBXPh Q 5Q3Rd. these b h stex eaten e eaili n herl 3?;h wth e Figur,e-,6}sl1 wsthepad4Qren1o 29 1 Fi u e w -we l .p ex a p w-s Eh inay belsubs'titutcd forlthe pad 40, the sp erical ;pad,'being probably capable of production at asmaller cosflinlarge quantities. igui'es 8,9 and. dQshow a slightly idi fferent form of the invention in which the yoke-liaving depending side -bars 5l is;secured vto cross head or plunger ,niember 5 by means of, ournals553 :formed .on l-the cross head or .plunger.52,,and seated in suit: able ournal bearings 54 in the, side bars 51 of the yoke 50 near the, lower ,ends.;., The ram 55 is chambered asin the previousinstance to receive-and enclose,the cross head or plunger 52, and the ram isrslottedat'the sides in the direction of its axisat 56. The cross head 5 2 has projecting cars 57 passing through. the. ,slots 56in theram parallel to the axis .and terminatingin journals 53 already described. These journals and the side bars 51 occupy outer enlarged slots 51 in the outer surfacev of the ram. Within thechamber or cavity 58'i11 .tl 1e ram are the. pads59 and 60'above and beloiv-thecross head 52, the respective pads bearingagainst the'corresponding sides of. the cross head-52. The upper pad 59also bears against ,a; suitable cover; 61 closing theucavity, 58 in the ram at the vtop. I and, suitably secured to -the top ofthe ram and-the pad 60. bears at its lower side against thebottom of the ram. The pads 59 and,-60, illustrated in Fig ures 10 and.l1,:are shown-as in the formof shortcylinders', each having'a centrally depressed portion on'the top at 64in whlch '15- shown as located. a suitable type of inflation.

valve 65 which may be closed by a screw cap 66 shown as square for convenient engagement with a socket Wrench or in any suitable manner.

The hammer or percussive tool as shown in each instance is provided at its lower end with a tool bushing 68 in which a tool is intended to be inserted as best shown in Figure 4, the end of the tool shank projecting beyond the bushing as at 69 into the path of the ram.

In the operation of the tool the cable 13 being connected to a convenient source of electricity, and the current being controlled by means of a switch operated by the finger lever 13', the motor 1 is energized and controlled, started, stopped, etc.

The rotary motion of the motor is communicated by and through the gear train 1.0, 11, 12, 14, 15 to the crank shaft 16 and to the crank disk 19, carrying crank pin 20 whereby the rotary motion is communicated to the cross arm 24 of the yoke 25 and hence by way of the arms 30, 31 to the cross head 34, which in the preferred form of the invention shown is located within the central cavity 36, Within the ram 6. Thus the reciprocating motion of the yoke is transmitted to the cross head 34 in the ram.

The pneumatic pads 40, 41 on each side of the cross head transfer the harmonic motion of the yoke and cross head modified by the resiliency of the pads to the ram, which is shown as chambered at 39' and 40 to fit the pads though this is not an absolutely essential provision.

As the ram is thus reciprocated by the motion of the cross head imparted thereto through the pads 39, 40, it is brought into contact at the end of each stroke with the tool shank 69 projecting upwardly from the bushing 68.

The modified form, Figures 8, 9 and 10, has the same operation as that described, the pad, Figures 10 and 11, being inflated when required by way of the valve 65, or the pads may be made as shown in Figures 6 and 7 without valves, to be thrown away when they have so deteriorated as to lack the necessary resiliency.

It is of interest that the values or relative values of the resilient properties of the pads as compared with the mass of the ram may be so selected that the ram has a natural period of vibration or oscillation which is equal to or an integral factor of the speed of rotation of the crank, i. e., the speed of the crank is a multiple of the speed of vibration of the ram. Preferably the ram makes a single oscillation or stroke for each two or more complete revolutions of the crank though this element may be so selected as to give a stroke of the ram for each revolution of the crank. In this way the movements or speed of the ram becomes greater than of'importancein that-it servesvery eflicient ly. ;to prevent the application bf! undue stress to-the-igean teeth', keys, sh'afts, etc: :l-im n I I have thus fdescribed; specifically and .=in detail. I a poritable: hammer; embodying; 1 the features of my invention inr-thel prefenred form a in oirden .that t the nature; 'mannn not operation andv/construction: and-gusing. the same "may be fully understood, @howelven," itlle terms 'r-herei-nf are: used! idescriptivel-yi rather than in-a; limiting, (sense: and ,--the scope of I the -.invent'ioniis; defined! inane olaimsm fWhat- I- claim: .as new and; desire :to isecure by.Letters'Patcnt is: w ll] of ail-amigo e-Jbi. 5 1. [The -,-dembination Limaiportab QVPQWBI" drivenmpercumive tooll of'msourch qfi rotarfy motione'nleans gfor transiorniingwotarly into reciprocating anotion, lancrosszhead-r grecip'ro', cated' thereby, a 2'ram,=' aepneumatioipad lin the :formlzof a gas A inflatedsbag for: transmit ting: theamotion =oflthe-cross head-atouthez mm, the rani being. i of heavyiconstnuetiomilhaw ing a central cavitya :plate iclosingither rear end ot 1 the Lcavity; and meanswfioii securing the plate imposition; aipa'd seat oarnied by the plate and. a pad seat sin Ethe- @forwardend of the ramysaid seatsibeing disposedrtoward the center of the :la lllyfiiii yoke marrying the c1'ossheadwhich is between fthe 'saidiseats and provided with corresponding seatsmn its lop; posite sides disposed; toward a said respectiveseats on s theplate and ram, (thepneumatic pads being-located on each SldQXOf-ithG'QI'OSQ- head i between and I engaging; the oppositely disposed seats of the crosshea'dwand; ram-and plate,'the plate being apertured-to pass; the

()ke. 1', i l fai' ilgi -12. The combination irnauportablelpower driven percussive toolofaacsouftei of meoip rocating motion, across head to -.which said reciprocatingmotion isappliedfla ram partially enclosing'the. cross; head and adapted to reciprocate relativelywthereto a :pneumaticipad in the form of a gas inflated bag on each side of the cross headiintheudb reetion of motion and between the cross head and the r'am transmitting the reciprocating motionof the cross head to: the ram the cross head beingprovided with-two seats'i for the respective bags for. transmitting; the thrust of the crosshead to the bags, the seats being disposed in the-two. opposite directions of reciprocation and the ram having corresponding seats engaging the bags from the sides opposite to those engaged by the cross head seats for transmitting to the ram a so . 5 of the barrel, a source of rotary motion,

the thrust applied to the bags by the cross-- head:

-3. The-combination in a portable power drivennpercussive tool of a source of rotary motion, a crank, a yoke and means connecting-the crank to the yoke, a reciprocating ram, a guide therefor, the yoke having a crosshead partially enclosed by the rain which. has two abutments spaced apart, one on each side of vthe cross head and a pneumatic pad in the form of a gas inflated bag on each side of the cross head between said 5 cross head and the-adjacent abutment wherebythe inotion of the cross head is communicated'to the ram in a form modified by the yielding'of the pneumatic element, the cross head being'provided with two seats for the respective bags for transmitting the thrust of the er'osshead-to the bags, the seats being disposed in the two opposite directions of reciprocation and the ram having corre sponding seats engaging the bags from the sides opposite to those engaged by the cross head seats for tra-nsn'iitting to the ram the thrust applied to the bags by the'crosshead. v 4; The combination in a portable power driven: percussion tool of a barrel, a hollow cylindr cal ram slotted at the sides mounted to rreciprocate in the direction of the length of the barrel, a source of rotary motion, a crank, a yoke operated thereby, the yoke having across head mounted to reciprocate in the hollow of the ram, said ram being slotted at the sides to accommodate the yoke, the cross head having "means extending through the slots into engagement with the yoke, and resilient means in the form of agas inflated-bag between the cross head and the ram on each side of the cross head in the direction of reciprocation.

5.- The combination in a portable power driven percussive tool of a barrel, a hollow cylindrical ram slotted at the sides mounted to reciprocate in the direction of the length a crank operated thereby, a yoke having a cross head mounted to reciprocate in the hollow of the ram, said ram being slotted at the sides to accommodate the yoke, the cross head having means extending through the slots into engagement with the yoke, said means on the cross head having journals projecting therefrom and the yoke having corresponding journal bearings to receive the same, and a pneumatic pad between the cross head and the ram on each side of the cross head in the direction of reciprocation.

Signed by me at Towson, Baltimore County, Maryland, this 18th day of April,

1931. ALONZO G. DECKER. 

